LC-MSMS assays of urinary cortisol, a comparison between four in-house assays.
Clin Chem Lab Med
; 56(7): 1109-1116, 2018 06 27.
Article
en En
| MEDLINE
| ID: mdl-29306912
ABSTRACT
BACKGROUND:
Twenty-four hour urinary free cortisol (UFC) determination can be used for screening and follow-up of Cushing syndrome (CS). As immunoassay methods lack specificity for UFC measurement, the use of high-performance liquid chromatography coupled to mass spectrometer (LC-MSMS) is recommended. The aim of our study was to compare UFC results using four LC-MSMS methods performed in four independent laboratories in order to evaluate interlaboratory agreement.METHODS:
Frozen aliquots of 24-h urine samples (78 healthy volunteers and 20 patients with CS) were sent to four different laboratories for analysis. Following liquid-liquid or solid-liquid extraction, UFC were determined using four different LC-MSMS assay.RESULTS:
UFC intra- and interassays variation coefficients were lower than 10% for each centre. External quality control results were not significantly different. UFC normal ranges (established from healthy volunteers) were 17-126, 15-134, 12-118 and 27-157 nmol/day, respectively. Classification of UFC from healthy volunteers and patients with CS using a 95th percentile threshold was similar. However, for extreme UFC values (<50 or >270 nmol/day), negative or positive bias was noted.CONCLUSIONS:
Even for highly specific methods such as LC-MSMS, variations of results can be found depending on analytical process. Validation of LC-MSMS methods including determination of the reference range is essential.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Hidrocortisona
/
Cromatografía Líquida de Alta Presión
/
Espectrometría de Masas en Tándem
Tipo de estudio:
Clinical_trials
/
Diagnostic_studies
Límite:
Adolescent
/
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Clin Chem Lab Med
Asunto de la revista:
QUIMICA CLINICA
/
TECNICAS E PROCEDIMENTOS DE LABORATORIO
Año:
2018
Tipo del documento:
Article
País de afiliación:
Francia